Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
1999-07-28
2001-11-13
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S160000, C526S943000, C502S104000, C502S117000, C502S152000
Reexamination Certificate
active
06316556
ABSTRACT:
The present invention relates to an olefin polymerization catalyst composition, in particular a composition comprising a metallocene and an aluminoxane or a reaction product thereof. The invention also relates to a process for preparing such an olefin polymerization catalyst composition and to the use of such an olefin polymerization catalyst composition for the polymerization of olefins.
In many olefin polymerization processes using a single site catalyst, homogeneous catalyst compositions based on a metallocene procatalyst and an aluminoxane cocatalyst have been used. By “homogeneous” is in this paper meant a dissolved or liquid catalyst, or a catalyst obtained by precipitation, evaporation or crystallization from solution or by solidification of liquid (e.g. melt).
According to S. Srinvasa Reddy, Polymer Bulletin, 36 (1996) 317-323, the polymerization activity of tetraisobutyldialuminoxane cocatalyst was clearly lower than the activity of methylaluminoxane cocatalyst. This reflects the prevailing general opinion, that only methyl aluminoxane as a cocatalyst gives satisfactory polymerization catalyst activities.
We have now surprisingly found that olefin polymerization may be carried out effectively using as a catalyst the combination of a metallocene and an aluminoxane other than methylaluminoxane where the metallocene contains a ring-substituted homo- or heterocyclic cyclopentadienyl sandwich ligand.
Thus viewed from one aspect the invention provides an olefin polymerization catalyst composition comprising a metallocene and an aluminoxane or a reaction product thereof, characterized in that said metallocene contains a ring-substituted homo- or heterocyclic cyclopentadienyl sandwich ligand and in that said aluminoxane contains alkyl groups containing at least two carbon atoms.
The catalyst composition of the invention is particularly advantageous since higher alkyl aluminoxanes, i.e. aluminoxanes containing alkyl groups containing at least 2 carbon atoms, may be prepared which are more uniform and more readily characterizable than methylaluminoxane, a material which is generally a mixture of several linear or cyclic structures. Use of more readily characterized aluminoxane co-catalysts offers the possibility of greater control and reproducibility of olefin polymerization. Also the storage stability of higher aluminoxanes is much better. The structure of the higher aluminoxanes will not change during storage, which is the case with MLAO.
The higher alkyl aluminoxane used according to the invention preferably contains C
2-10
alkyl groups. especially branched alkyl groups, e.g. ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, tert-butyl, i-butyl, n-pentyl, iso-amyl, sec-amyl, tert-amyl, iso-hexyl, sec-hexyl, or tert-hexyl groups. Particularly preferably the higher alkyl aluminoxane contains C
3-6
alkyl groups, especially branched alkyl groups.
The metallocene used according to the invention preferably includes a catalytically active transition metal or lanthanide complexed by one or more, e.g. 1 or 2 homo- or heterocyclic cyclopentadienyl ligands. Where the metallocene contains more than one cyclopentadienyl ligand moiety, then a non ring-substituted cyclopentadienyl ligand moiety may be present. However it is preferred that all the cyclopentadienyl ligand moieties be ring-substituted.
Ring substitution may be for example by pendant groups (e.g. hydrocarbyl or hydrocarbyloxy groups optionally attached via heteroatoms such as O, N, S, P, Si or Ge or via multiply bonded carbon atoms), by fused rings (e.g. such as to produce fused bicyclic or polycyclic structures with 5- and 6 membered homo- or heterocyclic rings, which (other than one five membered ring) may be saturated or unsaturated, e.g. indenyl, tetrahydroindenyl, fluorenyl and octahydrofluorenyl groups), by bridging groups attached to the metal or to a second optionally ring-substituted homo- or heterocyclic cyclopentadienyl ring (for example with the linker moiety providing at least one backbone atom selected from carbon, silicon, oxygen, sulphur, nitrogen and phosphorus, e.g. being an alkylene or silylene bridge), or by combinations of such substituents, for example with bridging or pendant groups being attached to rings fused to the cyclopentadienyl ligand moiety rather than directly to the cyclopentadienyl ring.
The ring substituent(s) on the cyclopentadienyl ring are preferably such as to permit an extension to the &pgr;-electron system of the cyclopentadienyl ring, especially preferably such as to further disperse the negative charge on the ring; thus the ring is especially preferably substituted by &pgr;-electron withdrawing groups, e.g. polyatomic groups attached via heteroatoms such as O, S, N or P or via multiple bonded carbons.
The catalyst composition of the invention may comprise the metallocene and the higher alkyl aluminoxane either unreacted or more preferably as their reaction product. The metallocene, aluminoxane or metallocene:aluminoxane reaction product may if desired be on a particulate support, e.g. a porous inorganic or inorganic material (e.g. silica) or alternatively they may be in solution in an organic solvent. If desired, one of the metallocene and the aluminoxane may be on a particulate support with the other present as a solid, as a liquid or in solution. If desired the metallocene and aluminoxane may be brought into contact only in the olefin polymerization reactor or while being dosed into the reactor.
Viewed from a further aspect the invention provides the use of an aluminoxane containing alkyl groups containing at least two carbon atoms as a co-catalyst with a metallocene pro-catalyst containing a ring-substituted homo- or heterocyclic cyclopentadienyl sandwich ligand for the polymerization of an olefin.
Viewed from another aspect the invention provides the use of a metallocene containing a ring-substituted homo- or heterocyclic cyclopentadienyl sandwich ligand as a pro-catalyst with an aluminoxane co-catalyst containing at least two carbon atoms for the polymerization of an olefin.
Viewed from a still further aspect the invention provides the use as a catalyst for olefin polymerization of the reaction product of an aluminoxane containing alkyl groups containing at least two carbon atoms and a metallocene containing a ring-substituted homo- or heterocyclic cyclopentadienyl sandwich ligand.
Viewed from a yet still further aspect the invention provides a process for the preparation of an olefin polymerization catalyst, said process comprising contacting a metallocene pro-catalyst containing a ring-substituted homo- or heterocyclic cyclopentadienyl sandwich ligand with an aluminoxane containing alkyl groups containing at least two carbon atoms, preferably in an organic solvent or solvent mixture in which said metallocene and aluminoxane are soluble and optionally in the presence of a porous particulate support, and if desired recovering the reaction product of said metallocene and aluminoxane, preferably supported on said particulate support.
Viewed from a yet still further aspect the invention provides a method of olefin polymerization comprising contacting an olefin with a metallocene:aluminoxane catalyst composition, characterized in that as said catalyst composition is used a metallocene pro-catalyst containing a ring-substituted homo- or heterocyclic cyclopentadienyl sandwich ligand and an aluminoxane co-catalyst containing alkyl groups containing at least two carbon atoms or the reaction product thereof.
Thus using the present invention one may replace MAO as the olefin polymerization co-catalyst in homogeneous catalyst compositions. Moreover, using the present invention one may produce a homogeneous olefin polymerization catalyst composition suitable for use in gas phase, slurry phase or liquid/solution phase polymerizations.
In a preferred embodiment, the process of the invention involves contacting
a) a metallocene of the general formula (1):
(C
p
Y
q
)
m
MX
n
Z
o
(1)
wherein Cp or each same or different Cp is one of a mono- or polysubstituted, fused or non-fused
Kallio Kalle
Kauhanen Jyrki
Knuuttila Hilkka
Birch & Stewart Kolasch & Birch, LLP
Borealis Technology Oy
Harlan R.
Wu David W.
LandOfFree
Homogeneous olefin polymerization catalyst composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Homogeneous olefin polymerization catalyst composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Homogeneous olefin polymerization catalyst composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2577231